The present invention is an input engaging clutch wherein the clutch engages by turning the input to the clutch. When the input to the clutch stops turning, the clutch disengages the output from the input.
A typical electric wrap spring clutch includes an input, an output and a wrap spring, which transfers torque from the input to the output. Typically, a control piece is attached to the spring to controllably wrap the spring down onto a hub when a signal voltage is provided and the input is rotated, thereby engaging the hub. When the control signal is removed the control piece is freed allowing the spring to unwrap and disengage the hub. In some applications it is desirable to energize and de-energize the clutch each time the input to the clutch is energized and de-energized. In this configuration, however, the clutch must receive a control signal that will actuate the control piece to engage and disengage the clutch each time that the input is energized and de-energized. A clutch that allows engagement and disengagement of the input and output without requiring a control signal would be desirable in certain applications.
The present invention is directed to an input engaging clutch. The input engaging clutch has a rotatable input that is capable of being rotated and capable of being held stationary. The clutch has a wrap spring that is coupled to the input. The wrap spring has an equilibrium state and rotates with the input when the input is rotating. The clutch also has a damper mechanism that is coupled to the spring such that the damper mechanism allows the spring to change from its equilibrium state to a flexed statexe2x80x94either wrapping open or wrapping downxe2x80x94when the input is rotated. In one embodiment, the clutch has a rotatable output that is positioned relative to the spring in such a way that the output rotates synchronously with the input when the spring is in its flexed state and rotates independently of the input when the spring is in its equilibrium state.